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Subject[PATCH 01/25] mm/um: Fix extra accounting for page fault retries
Date
When page fault retried, we should only do the accounting once rather than once
for each page fault retry.

CC: Jeff Dike <jdike@addtoit.com>
CC: Richard Weinberger <richard@nod.at>
CC: Anton Ivanov <anton.ivanov@cambridgegreys.com>
CC: linux-um@lists.infradead.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/um/kernel/trap.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 8f18cf56b3dd..d162168490d1 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -34,6 +34,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
pte_t *pte;
int err = -EFAULT;
unsigned int flags = FAULT_FLAG_DEFAULT;
+ vm_fault_t fault, major = 0;

*code_out = SEGV_MAPERR;

@@ -73,9 +74,8 @@ int handle_page_fault(unsigned long address, unsigned long ip,
}

do {
- vm_fault_t fault;
-
fault = handle_mm_fault(vma, address, flags);
+ major |= fault & VM_FAULT_MAJOR;

if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
goto out_nosemaphore;
@@ -92,10 +92,6 @@ int handle_page_fault(unsigned long address, unsigned long ip,
BUG();
}
if (flags & FAULT_FLAG_ALLOW_RETRY) {
- if (fault & VM_FAULT_MAJOR)
- current->maj_flt++;
- else
- current->min_flt++;
if (fault & VM_FAULT_RETRY) {
flags |= FAULT_FLAG_TRIED;

@@ -103,6 +99,11 @@ int handle_page_fault(unsigned long address, unsigned long ip,
}
}

+ if (major)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+
pgd = pgd_offset(mm, address);
p4d = p4d_offset(pgd, address);
pud = pud_offset(p4d, address);
--
2.26.2
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